1. Field of the Invention
This invention relates to body vessel clamps particularly adapted for occluding blood vessels within the cranial or spinal cavity.
2. Discussion of the Prior Art
Temporary occlusion of body vessels to prevent the flow of fluid within a vessel during surgical operations has long been necessary. In 1960 Jacobson and Suarez published a fundamental work clearly establishing a successful technique for uniting vessels of only 1-2 mm in diameter. See Jacobson, J.H. and Suarez, E.I., "Microsurgery in Anastomosis of Small Vessels", Surgical Forum, Clinical Congress 1960 Vox XI, p. 243-253, Chicago: American College of Surgeons. A vast array of mechanical contrivances have since been developed particularly to facilitate the microvascular surgeon in accomplishing this result within the least possible time while simultaneously minimizing vessel trauma. Early in the development of the microvascular art, only relatively large excessively powerful metal spring clamps such as bulldog clamps were available. See Chase, M.D. and Schwartz, S.I., "A Technique of Small Artery Anastomosis," Surgical Gynecology and Obstetrics, Vol. 116, pages 381-84, 1963. In addition to being excessively large, these conventional clamps failed to adequately maintain a stable anastomotic position. In this regard, some experts in the field have suggested the use of traction stitches, Cobbett J. "Small Vessel Anastomosis", British Journal of Plastic Surgery, Vol. 20, pages 16-20, 1967 and O'Brien B Mc et al; "Microvascular Surgical Technique", Medical Journal of Australia vol. 1, pages 722-775, 1970. Microvascular occluding units employing a pair of vascular clips bonded together by means of a slender frame has proved useful in maintaining vessel ends in proximity to one another during the suturing process. See Henderson P.N., et al., "An Adjustable Double Microvascular Clamp", Medical Journal of Australia, Vol 1, pages 715-717 1970. In some instances the slender frame bonding two vascular clips to one another may have "cleats" for attaching preliminary anastomotic sutures and thereby stabilizing the site of union. See Acland, R., "A Device for Holding Stay Sutures and a New Vascular Clamp", Surgery, Vol. 75, pages 185-187, February 1974. While any or all of the above mentioned techniques may be of particular value for more exposed sites of microvascular union (see Lendray, P. "Anastomosis of Digital Vessels", Medical Journal of Australia, Vol. 2, pages 723-725, 1969) they frequently prove awkward in the cramped intracranial and intraspinal operative fields, Yasargil, M.G. and Donaghy, R.M.P., "Microvascular Surgery", C. V. Mosby Co., St Louis, 1967.
Within the patent literature the need for an atraumatic vessel occluder has been recognized as disclosed in U.S. Pat. No. 3,880,166 to Fogarty. The Fogarty patent discloses an instrument for occlusion of small blood vessels including a substantially rigid plastic pad having a throat at one end and a passageway at the other end for receiving a resilient tape which may be selectively positioned to entrap and occlude a blood vessel between the pad and one end of the tape. While useful in many situations, the Fogarty clamp does not readily permit control of increased clamping pressure to a level which is just sufficient to occlude the vessel yet insufficient to cause vessel trauma. Furthermore, the Fogarty clamp tends to pinch the occluded vessel in a localized area defined by the width of the flexible tape being used thereby increasing the possibility of injury to the vessel. Other types of vessel occluding clips are known which do not apply such localized pressure such as disclosed in U.S. Pat. Nos. 3,865,944 to Sandi; 3,856,016 to Davis and 3,840,018 to Heifetz but these clips all require clumsy application instruments which are difficult to maneuver within small body cavities and which impede the surgeon's ability to accurately control the clamping pressure.
Techniques for occluding other body vessels have been suggested for application to blood vessel. For example, Berman, H. et al ("Method of Intestinal Anastomosis Without the Use of Clamps," Annals of Surgery, April 1953, pages 548-550) discloses the use of a piece of foam wrapped about a body vessel and pulled tight by means of a surrounding suturing line. The difficulty of inserting, positioning and tying a piece of foam rubber around a very small blood vessel by means of a separate suturing line within an extremely small body cavity is self evident. In summary the prior art has failed to teach a body vessel clamp which satisfies the sometimes conflicting goals of operability in extremely small spaces plus minimization of vessel trauma.